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authorAlexander Aring <aahringo@redhat.com>2021-11-02 22:17:18 +0300
committerDavid Teigland <teigland@redhat.com>2021-11-02 22:39:20 +0300
commit3cb5977c5214c219b2859f926ed547480d53fdde (patch)
treef321ca0c0e1f397073f194180f7e8043cea747aa /fs/dlm
parent164d88abd7608e869b7617d5ff8893344fdda759 (diff)
downloadlinux-3cb5977c5214c219b2859f926ed547480d53fdde.tar.xz
fs: dlm: ls_count busy wait to event based wait
This patch changes the ls_count busy wait to use atomic counter values and wait_event() to wait until ls_count reach zero. It will slightly reduce the number of holding lslist_lock. At remove lockspace we need to retry the wait because it a lockspace get could interefere between wait_event() and holding the lock which deletes the lockspace list entry. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs/dlm')
-rw-r--r--fs/dlm/dlm_internal.h3
-rw-r--r--fs/dlm/lockspace.c33
-rw-r--r--fs/dlm/requestqueue.c2
3 files changed, 20 insertions, 18 deletions
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index fd1c7a8c4485..019931804af9 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -548,8 +548,9 @@ struct dlm_ls {
uint32_t ls_generation;
uint32_t ls_exflags;
int ls_lvblen;
- int ls_count; /* refcount of processes in
+ atomic_t ls_count; /* refcount of processes in
the dlm using this ls */
+ wait_queue_head_t ls_count_wait;
int ls_create_count; /* create/release refcount */
unsigned long ls_flags; /* LSFL_ */
unsigned long ls_scan_time;
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index 4e4181304ca1..2e51bd2bdacc 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -314,7 +314,7 @@ struct dlm_ls *dlm_find_lockspace_global(uint32_t id)
list_for_each_entry(ls, &lslist, ls_list) {
if (ls->ls_global_id == id) {
- ls->ls_count++;
+ atomic_inc(&ls->ls_count);
goto out;
}
}
@@ -331,7 +331,7 @@ struct dlm_ls *dlm_find_lockspace_local(dlm_lockspace_t *lockspace)
spin_lock(&lslist_lock);
list_for_each_entry(ls, &lslist, ls_list) {
if (ls->ls_local_handle == lockspace) {
- ls->ls_count++;
+ atomic_inc(&ls->ls_count);
goto out;
}
}
@@ -348,7 +348,7 @@ struct dlm_ls *dlm_find_lockspace_device(int minor)
spin_lock(&lslist_lock);
list_for_each_entry(ls, &lslist, ls_list) {
if (ls->ls_device.minor == minor) {
- ls->ls_count++;
+ atomic_inc(&ls->ls_count);
goto out;
}
}
@@ -360,24 +360,24 @@ struct dlm_ls *dlm_find_lockspace_device(int minor)
void dlm_put_lockspace(struct dlm_ls *ls)
{
- spin_lock(&lslist_lock);
- ls->ls_count--;
- spin_unlock(&lslist_lock);
+ if (atomic_dec_and_test(&ls->ls_count))
+ wake_up(&ls->ls_count_wait);
}
static void remove_lockspace(struct dlm_ls *ls)
{
- for (;;) {
- spin_lock(&lslist_lock);
- if (ls->ls_count == 0) {
- WARN_ON(ls->ls_create_count != 0);
- list_del(&ls->ls_list);
- spin_unlock(&lslist_lock);
- return;
- }
+retry:
+ wait_event(ls->ls_count_wait, atomic_read(&ls->ls_count) == 0);
+
+ spin_lock(&lslist_lock);
+ if (atomic_read(&ls->ls_count) != 0) {
spin_unlock(&lslist_lock);
- ssleep(1);
+ goto retry;
}
+
+ WARN_ON(ls->ls_create_count != 0);
+ list_del(&ls->ls_list);
+ spin_unlock(&lslist_lock);
}
static int threads_start(void)
@@ -481,7 +481,8 @@ static int new_lockspace(const char *name, const char *cluster,
memcpy(ls->ls_name, name, namelen);
ls->ls_namelen = namelen;
ls->ls_lvblen = lvblen;
- ls->ls_count = 0;
+ atomic_set(&ls->ls_count, 0);
+ init_waitqueue_head(&ls->ls_count_wait);
ls->ls_flags = 0;
ls->ls_scan_time = jiffies;
diff --git a/fs/dlm/requestqueue.c b/fs/dlm/requestqueue.c
index d0cf68570dcf..ccb5307c21e9 100644
--- a/fs/dlm/requestqueue.c
+++ b/fs/dlm/requestqueue.c
@@ -127,7 +127,7 @@ static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid)
uint32_t type = ms->m_type;
/* the ls is being cleaned up and freed by release_lockspace */
- if (!ls->ls_count)
+ if (!atomic_read(&ls->ls_count))
return 1;
if (dlm_is_removed(ls, nodeid))